Arthritis and other rheumatic conditions (e.g., gout, lupus, and fibromyalgia) affect approximately 46 million adults in the United States, resulting in substantial disability and costs of $128 billion annually. Because U.S. adults are living longer and the number of persons in older age groups is growing, the number of U.S. adults living with chronic conditions such as arthritis likely will increase. The number of U.S. adults with doctor-diagnosed arthritis has been projected to reach nearly 67 million adults by the year 2030, including 25 million adults who are expected to have arthritis-attributable activity limitations. This report supplements those estimates by projecting the number of adults aged >/=18 years in each state who will have doctor-diagnosed arthritis and arthritis-attributable activity limitations in 2030. The results indicate that, among 48 states, the median projected increase in doctor-diagnosed arthritis from 2005 to 2030 will be 16%; a total of 14 states are projected to have increases of 30% to 87%. Greater use of existing evidence-based interventions and development of new interventions aimed at decreasing pain, improving function, and delaying disability associated with arthritis are needed to reduce the impact of these projected increases, particularly in those states that will be most heavily affected.